The upcoming docudrama about the early days of production on Doctor Who— called An Adventure in Space and Time—hascast the man to play First Doctor actor William Hartnell. Known to Harry Potter fans as Argus Filch, David Bradley will fill the curmudgeonly shoes of the late Hartnell in the Mark Gatiss-penned project. Of course, Bradley recently showed up on Doctor Who-proper, playing an evil space-poacher in “Dinosaurs on Spaceship.” Reportedly, Bradley was so excited to be asked by Gatiss that he “almost bit his hand off.” Luckily, no hands had to be regrown, Gallifreyan style.

An Adventure in Space and Time is filming in February and is set to air late in 2013.